CASELLA-MILLER DEEP-SEA THERMOMETER. 897 



J^xperimenia on difference of temperature, in a hath of ice-icater not 



agitated. 



No. 1. 



No. 1, bulb immersed in contact with ice stood 33°, lowered to 100° 

 stood 390. 



No. 2, bulb immersed in contact with ice stood 33^.2, lowered to 100° 

 stood 3GO. 



No. 4, bulb immersed in contact with ice stood 33°, lowered to 100° 

 stood 370. 



No. 5, bulb immersed in contact with ice stood 33^.4, lowered to 100° 

 stood 30°. 



The differences arising from differences in length of stem causing tlie 

 bulbs to reach different strata. 



Experiment No. 2. 



No. 1 and No. 2, lying flat on bottom of tub, with G inches of water, 

 3 inches of broken ice, recorded 42o.5. No. 2 was raised with pincers 2 

 inches, and fell to 40°. 



In addition to printed instructions I would respectfully suggest the 

 following: 



1. Keep thermometer at uniform temperature before and between low- 

 erings. 



2. Have two snaps on the line above the lead, to prevent delay in 

 bending on. 



3. Set and note indexes. 



4. Note time of reaching lowest depth, and be sure and keep the in- 

 strument at its depth over ten minutes, unless previous lowerings have 

 taught that the difference between surface and bottom temperatures is 

 less than requires this time. 



5. Do not count as dou-n the time wasted if the ship be dragging or 

 drifting and the line trailing out at an angle. 



6. In reading hold the instrument perpendicular, with the bottom of 

 the iudex on a level with the eye. 



7. On registering, note time and tides. 



If the mercury becomes badly disintegrated, and swinging and tap- 

 ping are of no avail, I have succeeded in getting the thermometer to 

 rights by this method : 



No. 15,720 was found damaged ; on the hot side the mercury was in 

 four parts, one bit 5° in length, separated from the rest by a space of 

 10°, and nearly as bad on the cold side. Every other means failing, 

 I placed it bulb up in the salinometer pot; having removed the ebonite 

 guard and turned on steam, the mercury mounted on the hot side and 

 formed a sphere at the lower part of the bulb, until nearly all coalesced, 

 leaving still a columnar portion in the tube. I removed it from the sali- 

 57 F 



